Since police officers began wearing body cameras in January 2014, the city of San Diego, California, has seen a massive change in the relationship between cops and residents — for the better.

According to a March 18 report from the Police Department for the City Council's Public Safety and Livable Neighborhoods Committee, from when the body cams first went into use through January 2015, complaints had fallen by 40.5% and the use of "personal body" force by officers was down 46.5%. The use of pepper spray dropped 30.5%, reports the Los Angeles Times.

"Body-worn camera technology is a win-win for both the officer and the community," Deputy Chief David Ramirez said in the report, which also noted that 600 officers currently use the cameras. The city plans to equip 1,000 officers with cameras by the end of 2015.

Basicly, the knowledge that they are being watched improves police behaviour, reducing both use of force and complaints. And that's a good thing. So, why haven't we done this yet?